1. Technical Field
The present invention relates to an inkjet recording apparatus that forms an image on a print medium by discharging ink from a plurality of ink heads and, more particularly, to a density adjustment module and a density adjustment method for adjusting the density in an image that is formed.
2. Background Arts
Conventionally, an inkjet type recording apparatus that forms an image by discharging ink from an inkjet recording head onto a print sheet is widely used. This type of recording apparatus includes a line inkjet recording apparatus in which ink heads are directly-aligned and recording is performed only by a sub scan, in which a print sheet is sent in the transfer direction. In a line inkjet recording apparatus, recording corresponding to one line at one time is performed successively to a print sheet.
An ink head of an inkjet recording apparatus includes a pressure chamber having a nozzle and in this recording apparatus, ink is discharged by pressurizing ink within the pressure chamber. However, the above-described line inkjet recording apparatus has such a problem that there occurs a density difference of ink discharged from each ink head because the discharge efficiency of ink differs from head to head even if the same voltage is applied, and therefore, an image having a tone jump is printed.
In order to solve such a problem, according to the technique disclosed in Patent Document (Japanese Patent Application Laid-Open No. 2006-137040), the density difference between heads is reduced by adjusting the voltage difference between ink heads based on the density characteristics within the head.